I used to have this phone, I wish I could remember which model it was (I think it was a sprint phone), if a call was coming in, you could hit the side button, and it would act like it was sending the called to voicemail, but you were still on the line listening. You could hit another button to answer the call, or let them leave a message. It was truly the greatest feature I've ever seen on a phone.

Sorry for going slightly off topic.

Yes, I also remember this. I was on sprint as well with an old samsung of some sort. If you hit the side button you could listen in on the other side even before they started to leave a voicemail - it was amazing and I truly have missed it ever since. Youd be surprised the things which were said prior to the actual voicemail haha.